This invention relates to circuit interrupters, and more specifically relates to a novel, single-pressure bottle type interrupter which is filled with a relatively static dielectric gas or medium wherein arc interruption is obtained by rotating the arc through the relatively static gas.
The novel interrupter of the present invention has application over a wide range of voltage and current ratings and is particularly applicable to relatively high voltage ratings, such as 15 kV and above. At the present time, a variety of different types of interrupters and circuit breakers are used for interruption of high voltage circuits, but each of these are relatively expensive and have numerous operational disadvantages. For example, vacuum interrupters and air magnetic interrupters are frequently used in connection with 15 kV and 38 kV metalclad switchgear circuits. The air magnetic interrupter is old and well known and is large and expensive and requires frequent maintenance. In the air magnetic interrupter, a pair of contacts separate and the arc drawn between the contacts is transferred to respective arc runners which guide the arc into an arc chute, where the arc can be cooled and deionized and extinguished. Some air magnetic circuit interrupters are also provided with a small puffer arrangement, whereby an air stream flows through the arc to assist its movement into the arc chute. The concept of transferring an arc from a pair of separating contacts and guiding the motion of the arc by means of arc runners will be seen hereinafter to be employed conceptually in the present invention. In addition, the concept of a limited puffer will also be seen hereinafter to be employed with the present invention.
Vacuum interrupters are also well known, but these are expensive and are subject to breakdown following an interruption action. Vacuum interrupters moreover cause "chopping" during interruption on some circuits and can produce high voltage on those circuits. Vacuum interrupters frequently employ an arrangement which causes the arc drawn between the separating contacts to spin around the contacts, thereby to more evenly distribute the heat created by the arc on any localized area of the contact. As will be seen hereinafter, the present invention employs the general concept of arc spinning, although this is done in a totally different context in the present invention.
Bulk oil breakers are well known for applications, for example, in 15 kV ranges and above, but bulk oil breakers again are large and are expensive. The bulk oil breaker employs the concept of drawing an arc between separating contact is in a relatively high dielectric medium and also employs the concept of generating high-pressure gases which blast through the relatively stationary arc. As will be seen hereinafter, the concept of a relatively high dielectric medium is employed with the present invention but in a different context than used in the bulk oil breaker.
At higher voltages, for example, 121 kV and above, various interrupting mediums have been used to interrupt an arc including oil and air blast. Such breakers are large and expensive and create periodic maintenance. Two-pressure sulfur hexafluoride breakers are also used at these higher voltages, but the two-pressure breaker is again large and complex and requires equipment for maintaining relatively high gas pressures. The concept of the air blast breaker, like the oil breaker, relies on the high speed movement of a dielectric fluid through a relatively stationary arc in order to cool and extinguish the arc. A similar concept is employed in the two-pressure SF.sub.6 interrupter wherein a relatively high speed movement of SF.sub.6 through a relatively stationary arc permits the extinguishing of the arc. The present invention employs the general concept of relative movement of an arc with respect to a dielectric fluid.
Puffer type circuit breakers are also used in relatively high voltage ranges where the movement of the contacts causes a rapid flow of gas which moves through a relatively stationary arc in order to extinguish the arc. Breakers of this type are large and require considerable operating power in order to move the pressure-generating equipment and become complex ane expensive and require periodic maintenance. The puffer breaker, like the two-pressure SF.sub.6 breaker, relies on a high speed blast of dielectric fluid, such as sulfur hexafluoride gas, through a relatively stationary arc in order to extinguish the arc.
The novel circuit interrupter of the present invention can be used in place of the above type circuit interrupters of the prior art as well as others not mentioned above over a wide range of rated voltages and over a wide range of continuous current and interrupting current ratings.
In a specific application, the device of the present invention is a hermetically sealed bottle interrupter that can replace presently available vacuum bottle interrupters for 15.5 and 38 kV power circuit breakers. In another aspect of the invention, structures are provided which can be employed with a vacuum, as well as a gas dielectric medium.
The novel sealed bottle interrupter of the invention may also be used in combination with and in series with a vacuum interrupter, or with another gas-filled bottle, to form a high voltage, high capacity power circuit breaker, as disclosed in copending application Ser. No. 609,161, filed Aug. 29, 1975, referred to previously. When used in that manner, for a so-called hybrid circuit breaker, the dielectric recovery capability and dielectric withstand capability of the dielectric gas-filled bottle of this application cooperates synergistically with the interruption and thermal recovery characteristics of the vacuum or other interrupter.